import java.util.Scanner;

//1:圆类有半径属性和圆周率属性，有求面积和周长的方法（把圆周率定义为static），用oop模拟。
public class CircularTest {
    public static void main(String[] args) {
        System.out.println("input r:");
        Scanner in = new Scanner(System.in);
        Circular ci = new Circular();
        ci.r = in.nextDouble();
        System.out.println("area:" + ci.area() + "\nperimeter:" + ci.perimeter());
    }
}